1. Field of the Invention
This invention relates to liquified normally solid forms of polyoxyalkylene block copolymers. The compositions of this invention are particularly useful in flowable pesticide concentrates.
2. Description of the Prior Art
Pesticidally-active compounds have conventionally been formulated as emulsifiable concentrates or as wettable powders. The emulsifiable concentrates have normally been the type of formulation preferred for pesticides which are soluble in organic solvents. Pesticides with limited solvent solubility have usually been formulated as wettable powders. Both of these formulation types present their own special problems.
Emulsifiable concentrates are based on one of our diminishing natural resources--petroleum. Because large amounts of solvents are required, emulsifiable concentrates can only become more expensive as time goes on. In addition to the economic considerations, it is becoming increasingly apparent that conservation of this valuable resource is imperative.
Wettable powders are dusty and breathing the dust can cause skin and eye irritation as well as illness. Disposal of the residue containing bag is also of growing concern, because children and those unfamiliar with the potential hazards might be exposed when the bag is discarded.
As a result of these problems, flowable formulations are becoming increasingly more prevalent. They are prepared by dispersing the finely divided pesticide ingredients in an aqueous medium to form a concentrated dispersion. For application this dispersion is further diluted with water. Flowable formulations provide the following advantages: little or no organic solvent required, virtual elimination of inhalation danger, and greatly reduced skin and eye irritation problems. In addition, container residues can easily be hosed into the spray tank prior to disposing the container.
The applications of polyoxyalkylene block copolymers, especially polyols containing high amounts of ethylene oxide, have been widely recognized and used as effective emulsifiers for pesticide concentrates. Because of their high ethylene oxide contents, these polyols are either paste or solid products, making their uses in formulating agricultural products cumbersome and very difficult, due to gel formation upon addition of water. In accordance with the prior art, it was discovered that certain alcohol ethoxylates, such as tridecyl alcohol, 6 mole ethoxylate or C.sub.18 alcohol 20 mole ethoxylate, plus water, are good solvents. However, agricultural chemical formulators have discovered that such alcohol ethoxylates are detrimental to long term stability of the pesticide concentrate. Further, the prior art compositions have presented problems related to gelling and often have viscosities that are too high to be readily pumpable from around room temperature, i.e., 20.degree. to 25.degree. C. up to 50.degree. C.
It has generally been believed, in accordance with the prior art, that to solubilize high ethylene oxide content polyols and prevent gel formation, the polyol must be added in small amounts, or incrementally, to chilled water, because water at room temperature or higher would cause gel formation.
Accordingly, it is a purpose of the instant invention to provide liquid compositions useful in pesticide concentrates which are readily pumpable at temperatures below 50.degree. C. and particularly at or about room temperature, which are non-gelling and which possess long term stability.